Mix your 1 1/2 cups graham cracker crumbs with the melted butter until it resembles wet sand. Press this firmly into the bottom of a 9x13 inch baking dish, creating an even layer. This becomes your crust, so don't skip the pressing step—you want it packed down tight. Pop it into the freezer while you make the filling.

In a large bowl, whisk together your softened cream cheese, 1 cup powdered sugar, and 1 tsp vanilla extract until completely smooth. No lumps allowed here—take about 2 minutes to get it silky. This creamy layer is what makes your patriotic icebox cake taste like dessert heaven.

In another bowl, beat your 1 cup heavy cream with the 1/2 cup granulated sugar until stiff peaks form, about 3-4 minutes. This whipped cream gets folded into your cream cheese mixture, so don't overbeat it past that point. Gently fold the whipped cream into the cream cheese until barely combined.

Stir your 2 tsp agar-agar powder into the cream mixture. This thickens everything up during chilling and helps your no bake red white blue cake hold its shape perfectly. Mix it in completely, breaking up any powder clumps.

Spread half of this cream mixture over your chilled crust layer. Then arrange your sliced strawberries on top in a single layer—this creates that red stripe of your patriotic icebox cake. Top the strawberries with the remaining cream mixture, spreading it smooth.

Layer your sliced blueberries on top of the cream, creating a blue stripe. Then arrange your sliced bananas as the white stripe—it looks stunning and tastes even better. You've literally just created an edible flag, and guests will go crazy for it.

Cover the whole thing with plastic wrap and refrigerate for at least 4 hours (overnight is even better). The agar-agar powder sets everything up, and the flavors meld together beautifully. Dust with 1/4 cup powdered sugar just before serving for that bakery-style finish.